Method of announcing replacement time of air filter in a heating, ventilating, and air-conditioning system of a vehicle

ABSTRACT

A method for announcing the replacement time of an air filter in an HVAC system of a vehicle includes the steps of inputting factors used for judging whether the air filter should be replaced; determining whether inside air or outside air is supplied; calculating a total amount of dust by calculating a dust concentration reduction per unit volume by considering a total amount of introduced air and an initial inside dust concentration if inside air is supplied, or calculating a total amount of dust using an amounts of air at a current operation level if outside air is supplied; determining whether the total amount of dust exceeds a reference amount of dust; and activating an indicator, such as an alarm or a warning light, if the total amount of dust exceeds the reference amount of dust.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based on, and claims priority from, KoreanApplication Serial Number 10-2005-0122040, filed on Dec. 12, 2005, thedisclosure of which is hereby incorporated by reference herein in itsentirety.

FIELD OF THE INVENTION

The present invention relates to a method of announcing the replacementtime of an air filter in a heating, ventilating and air-conditioning(HVAC) system of a vehicle, and more particularly, to a method ofannouncing the replacement time of an air filter in an HVAC system of avehicle that automatically announces the exact replacement timedepending upon the operating status of the HVAC system, including theoperating conditions, the characteristics of the air filter, andregional features.

BACKGROUND OF THE INVENTION

As is generally known in the art, an HVAC system of a vehicle is used asan automatic air conditioner, in which a heater and a cooler aremodularized in order to maintain the temperature in a passengercompartment at a level desired by the driver.

There are three conventional techniques for announcing the replacementtime of the air filter. In the first technique, pressure loss throughthe inlet and outlet of the air filter is measured. In the secondtechnique, the degree of contamination of the air filter is directlymeasured, for example with using an infrared sensor. In the thirdtechnique, the degree of contamination of the air filter is indirectlymeasured using an air flow speed sensor.

However, in each of the above three techniques, since a separate sensoris used to measure the amount of air, the air pressure, or the degree ofcontamination of the air filter, the cost and weight of the vehicleincrease, and it is difficult to install the HVAC system in the vehicle.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE INVENTION

The present invention provides a method for announcing the replacementtime of an air filter in an HVAC system of a vehicle which canautomatically announce the exact replacement time of an air filterdepending upon the operating conditions of an HVAC system of a vehicle,the characteristics of the air filter, and regional features.

A method for announcing the replacement time of an air filter in an HVACsystem of a vehicle according to an embodiment of the present invention,comprises the steps of inputting factors used for judging whether theair filter should be replaced; determining whether inside air or outsideair is supplied; calculating the total amount of dust by calculating thedust concentration reduction per unit volume using the total amount ofintroduced air and an initial inside dust concentration when it isdetermined that inside air is supplied, or calculating the total amountof dust using the amounts of air at respective operation levels and anair direction in accordance with the operation of a blower motor when itis determined that outside air is supplied; determining whether thecalculated total amount of dust exceeds a reference amount of dust whichis preset for the air filter; and activating an indicator, such as analarm or a warning light, when the total amount of dust on the airfilter exceeds the reference amount of dust.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the presentinvention, reference should be made to the following detaileddescription with the accompanying drawings, in which:

FIGS. 1 a and 1 b are a front view and an exploded perspective viewillustrating the construction of an HVAC system according to exemplaryembodiments of the present invention; and

FIG. 2 is a flow chart illustrating a method for announcing thereplacement time of an air filter in a heating, ventilating andair-conditioning system of a vehicle in accordance with an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in greater detail to embodiments of theinvention, an example of which is illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals will be usedthroughout the drawings and the description to refer to the same or likeparts.

Referring to FIG. 1 a, an HVAC system 100 includes an air inlet section20, a blower unit 30, and a heating and cooling unit 10. Referring toFIG. 1 b, the heating and cooling unit 10 includes an air supplyposition adjustment section 2 a, 2 b and 2 c for selecting an air supplyposition (e.g. front windshield, the driver's face, or the driver'slegs), an air flow direction adjustment section 6, and an airtemperature control section 4. The amount of air and the amount of dustfiltered by an air filter vary by the manipulation of the air supplyposition adjustment section 2 a, 2 b and 2 c, the air temperaturecontrol section 4, and the air flow direction adjustment section 6; aswell as the position of the air inlet section 20, and the operatinglevel of the motor of the blower unit 30.

Referring to FIG. 2, in order to automatically announce the replacementtime of an air filter in a heating, ventilating and air-conditioningsystem of a vehicle, factors used for judging whether the air filtermust be replaced are input (S10).

The input factors may include regional pollution levels. The values ofvariables are input in advance on the basis of the average dustpollution levels of various regions so that the air filter replacementperiod is short in heavily polluted regions and longer in relativelyunpolluted regions. In this way, diverse regional features can beconsidered when determining the replacement time of the air filter.

The input factors may further include the type of air filter; the airfilter replacement period is short for an air filter having a fine meshstructure and longer for an air filter having a coarse mesh structure.

The input factors may further include passenger compartment size. Thetotal amount of dust in the passenger compartment under an inside aircirculation mode varies with the volume of the passenger compartment.Thus, the difference in the amount of dust must be compensated fordepending upon the kind of car.

After the factors are input at step S10, whether inside air or outsideair is being supplied is determined (S20). As a result of thedetermination in step S20, if it is determined that inside air is beingsupplied, a heater controller calculates the amount of air, and thetotal amount of dust is calculated by calculating the dust concentrationreduction per unit volume using the initial inside dust concentration(S30, S60). On the other hand, as a result of the determination in stepS20, if it is determined that outside air is being supplied, and if ablower is not driven, a preset amount of air (e.g. 60 m³/h), whichindicates the average amount of air introduced into the car by airpressure under an outside air inflow mode) is used. If the blower isdriven, after the heater controller calculates the amount of air, anamount of dust V=QH is calculated (S60), where V is the total amount ofintroduced air, Q is the amount of air introduced per unit time, and His elapsed time.

The total amount of dust W=VC on the air filter is then calculated,where W is the total weight of dust, V is the total amount of introducedair as calculated above, and C is the concentration of dust.

After the total amount of dust is calculated in step S60, whether thecalculated total amount of dust exceeds a reference amount of dust whichis preset for the air filter is determined (S70). If the calculatedtotal amount of dust exceeds the reference amount of dust, an indicator,such as an alarm or a warning light, is activated to announce thereplacement time of the air filter (S80). If the calculated total amountof dust does not exceed the reference amount of dust, the calculatedamount of dust on the air filter is stored (S90).

In some embodiments, different pollution levels can be assigned todifferent regions. For example, due to the various running conditionsfor cars in Seoul, China and the U.S.A. which have different airpollution levels, the amounts of dust which accumulate on air filtersvary. Therefore, in a state in which the values of variables are inputin advance based on the average dust pollution levels of various regions(as compiled by an international environmental association), the airfilter replacement period is short in heavily polluted regions andlonger in less polluted regions.

As is apparent from the foregoing, the present invention providesadvantages in that, since the exact replacement time of an air filtercan be automatically announced to a consumer, it is possible to preventoffensive odors from being generated to be introduced into the passengercompartment of the vehicle and prevent a performance of an airconditioner or heater from being reduced due to the contamination of theair filter.

Although preferred embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A method of announcing the replacement time of an air filter in aheating, ventilating, and air conditioning system of a vehicle,comprising the steps of: inputting factors used for judging whether theair filter must be replaced; determining whether inside air or outsideair is supplied; calculating a total amount of dust, the calculating atotal amount of dust comprising: if inside air is supplied, calculatinga dust concentration reduction per unit volume by considering a totalamount of introduced air and an initial inside dust concentration; andif outside air is supplied, calculating the total amount of dust usingan amount of air at a current operation level and an air direction;determining whether the total amount of dust exceeds a reference amountof dust; and activating an indicator if the total amount of dust exceedsthe reference amount of dust.
 2. The method as defined in claim 1,wherein the factors comprise a regional pollution level, an air filtertype, and a passenger compartment volume of the vehicle.
 3. The methodas set forth in claim 1, wherein the step of calculating the totalamount of dust further comprises using a preset amount of air if ablower motor is not driven and outside air is supplied.
 4. The method asset forth in claim 3, wherein the preset amount of air is approximately60 cubic meters per hour.
 5. The method as set forth in claim 1, whereinthe total amount of introduced air V is calculated from V=Q H, where Qis an amount of air introduced per unit time, and H is time.
 6. Themethod as set forth in claim 1, wherein the total amount of dust W onthe air filter is calculated from W=V C, where V is a total amount ofintroduced air, and C is a concentration of dust.
 7. The method as setforth in claim 1, further comprising the step of: storing the totalamount of dust on the air filter if the total amount of dust on the airfilter does not exceed the reference amount of dust.